Typically, the spine is under continuous loading, for example loading of the spinous processes of the vertebral bodies, the facet, and the discs. The cervical spine may be loaded by the weight of the head, by gravity, or sometimes simply by carrying objects with the upper extremities. In addition, the load changes whether the vertebra is flexed forward or extended backward. When the vertebra is flexed forward, there may be an increased load on the disc and the anterior element. When the vertebra is extended posteriorly, there may be an increased load across the facet joints. As such, it may be beneficial to unload the vertebra, especially of the cervical spine.
Traditional traction devices and methods primarily rely on a pneumatic drive assembly for distraction. Pneumatic traction devices may include a carriage that moves relative to a support structure when pressurized. A user may operate a hand pump that is fluidly connected to the pneumatic drive assembly to inject pressurized air. The hand pump injects pressure into the pneumatic traction device thereby moving the carriage a variable distance. A pressure relief mechanism may be operated by the user to release pressure from the pneumatic traction device. Pneumatic devices may suffer from air pressure loss during use, difficulty with use of the hand pump, uncontrollable and impulsive traction release, non-adjustable traction angles and support features, and expensive and bulky pneumatic components.
More specifically, these pneumatic devices are driven by imprecise volumetric or pressure changes in fluids, not interaction between solid mechanical components. For example, volumetric or pressure changes may result in an applied pressure, which may not directly translate into a precise distraction distance, force, and/or angle with respect to portions of the body. Also, pneumatic devices may employ measurement gauges reflecting volume or pressure but may not provide a precise mechanism to indicate or control the distraction distance, for example in terms of millimeters. Moreover, pneumatic devices are unable to maintain a set distraction distance, because pneumatic pressure is gradually lost due to fluid compression or leakage throughout the pneumatic system. For precise distraction, cervical traction devices may control and maintain distraction to a precise distance, which may not be possible for a pneumatically driven system. Although volumetric or pressure changes may be an indicator of the pressure on the pneumatic device itself, reliance on volume or pressure changes may not translate to a repeatable and precise distraction distance, force, and/or angle necessary for effective treatment.
In addition, the atmospheric conditions may cause variations in traditional pneumatic devices. Depending on whether the temperature is colder or warmer, the pressure applied and measured may change. If humidity increases or decreases, the applied pressure may be different, for example based on the material characteristics of the pneumatic fluid or the body. Even at different altitudes, the atmospheric pressure may vary thereby inducing inaccuracy in devices relying on pressure. With any of these changes, pneumatic devices may apply and measure pressure with substantially varying accuracy. Pneumatic drive devices may be affected by environmental conditions (i.e. temperature, humidity, and altitude) that may only have a negligible effect on mechanical drive devices. Pneumatic devices may not be able to provide and maintain the precise and consistent distraction distances or forces that mechanical devices may provide. Also, considering the relevance of the distraction distance in treating conditions of the spine, pneumatic devices may be imprecise when compared to a device with measurable and controllable distraction distances.
There exists a need for traction devices and methods configured to provide ease of use, precise distraction forces and distances, adjustable traction angles and support components, controlled traction application and release, and reduction in unnecessary components.